An image forming apparatus that is responsive to a panel operation to display Web content and execute a function such as printing of the Web content is known. The image forming apparatus has a Web service processing unit (Web Service) that processes a Web service request. After a browser (a browser application) displays a page image on a screen, when a printing request is sent to a Web server, the server returns a Web service request corresponding to this request to the Web service processing unit. An image forming unit then prints the page image displayed on the screen. The Web service is a mechanism by which the function and services of the image forming apparatus are used via a network, by passing messages to and from the browser, and, when the Web service is used, the image forming apparatus requests authentication by log-in on the panel.
When a Web site that requires user authentication is used from the panel of the image forming apparatus, it is burdensome for the user to perform authentication for each access to the Web server. Thus, a single sign-on that requires the user to perform authentication only once is known.
However, even when the same user operates an image processing apparatus, authentication of the user has to be performed for each Web service. It is troublesome for the user to perform authentication again after moving to another page of the Web site on the panel.